From 3beb076950711e119269003e26d41e28e86a123f Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Tue, 14 Jan 2020 18:51:17 +0100
Subject: [PATCH] webdav: add very basic Client

---
 client.go            | 63 ++++++++++++++++++++++++++++++++++++++++++++
 elements.go          |  5 ++++
 internal/client.go   | 63 ++++++++++++++++++++++++++++++++++++++++++++
 internal/elements.go | 29 ++++++++++++++++++++
 4 files changed, 160 insertions(+)
 create mode 100644 client.go
 create mode 100644 elements.go
 create mode 100644 internal/client.go
 create mode 100644 internal/elements.go

diff --git a/client.go b/client.go
new file mode 100644
index 0000000..815b4a9
--- /dev/null
+++ b/client.go
@@ -0,0 +1,63 @@
+package webdav
+
+import (
+	"encoding/xml"
+	"fmt"
+	"net/http"
+	"strings"
+
+	"github.com/emersion/go-webdav/internal"
+)
+
+type Client struct {
+	c *internal.Client
+}
+
+func NewClient(c *http.Client, endpoint string) (*Client, error) {
+	ic, err := internal.NewClient(c, endpoint)
+	if err != nil {
+		return nil, err
+	}
+	return &Client{ic}, nil
+}
+
+func (c *Client) FindCurrentUserPrincipal() (string, error) {
+	r := strings.NewReader(`<?xml version="1.0" encoding="utf-8"?>
+<D:propfind xmlns:D="DAV:">
+  <D:prop>
+    <D:current-user-principal/>
+  </D:prop>
+</D:propfind>
+`)
+
+	req, err := c.c.NewRequest("PROPFIND", "", r)
+	if err != nil {
+		return "", err
+	}
+
+	req.Header.Add("Depth", "0")
+	req.Header.Add("Content-Type", "text/xml; charset=\"utf-8\"")
+
+	resps, err := c.c.DoMultiStatus(req)
+	if err != nil {
+		return "", err
+	}
+
+	if len(resps) != 1 {
+		return "", fmt.Errorf("expected exactly one response in multistatus, got %v", len(resps))
+	}
+	resp := &resps[0]
+
+	// TODO: handle propstats with errors
+	if len(resp.Propstats) != 1 {
+		return "", fmt.Errorf("expected exactly one propstat in response")
+	}
+	propstat := &resp.Propstats[0]
+
+	var prop currentUserPrincipalProp
+	if err := xml.NewTokenDecoder(propstat.Prop.TokenReader()).Decode(&prop); err != nil {
+		return "", err
+	}
+
+	return prop.Href, nil
+}
diff --git a/elements.go b/elements.go
new file mode 100644
index 0000000..28e85d7
--- /dev/null
+++ b/elements.go
@@ -0,0 +1,5 @@
+package webdav
+
+type currentUserPrincipalProp struct {
+	Href string `xml:"current-user-principal>href"`
+}
diff --git a/internal/client.go b/internal/client.go
new file mode 100644
index 0000000..3a83f74
--- /dev/null
+++ b/internal/client.go
@@ -0,0 +1,63 @@
+package internal
+
+import (
+	"encoding/xml"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"path"
+)
+
+type Client struct {
+	http     *http.Client
+	endpoint *url.URL
+}
+
+func NewClient(c *http.Client, endpoint string) (*Client, error) {
+	if c == nil {
+		c = http.DefaultClient
+	}
+
+	u, err := url.Parse(endpoint)
+	if err != nil {
+		return nil, err
+	}
+	return &Client{c, u}, nil
+}
+
+func (c *Client) NewRequest(method string, p string, body io.Reader) (*http.Request, error) {
+	u := url.URL{
+		Scheme: c.endpoint.Scheme,
+		User:   c.endpoint.User,
+		Host:   c.endpoint.Host,
+		Path:   path.Join(c.endpoint.Path, p),
+	}
+	return http.NewRequest(method, u.String(), body)
+}
+
+func (c *Client) Do(req *http.Request) (*http.Response, error) {
+	// TODO: remove this quirk
+	req.SetBasicAuth("simon", "")
+	return c.http.Do(req)
+}
+
+func (c *Client) DoMultiStatus(req *http.Request) ([]Response, error) {
+	resp, err := c.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusMultiStatus {
+		return nil, fmt.Errorf("HTTP multi-status request failed: %v", resp.Status)
+	}
+
+	// TODO: the response can be quite large, support streaming Response elements
+	var ms multistatus
+	if err := xml.NewDecoder(resp.Body).Decode(&ms); err != nil {
+		return nil, err
+	}
+
+	return ms.Responses, nil
+}
diff --git a/internal/elements.go b/internal/elements.go
new file mode 100644
index 0000000..7f84e12
--- /dev/null
+++ b/internal/elements.go
@@ -0,0 +1,29 @@
+package internal
+
+import (
+	"encoding/xml"
+)
+
+// https://tools.ietf.org/html/rfc4918#section-14.16
+type multistatus struct {
+	XMLName   xml.Name   `xml:"DAV: multistatus"`
+	Responses []Response `xml:"DAV: response"`
+	// TODO: responsedescription?
+}
+
+// https://tools.ietf.org/html/rfc4918#section-14.24
+type Response struct {
+	XMLName   xml.Name   `xml:"DAV: response"`
+	Href      string     `xml:"DAV: href"`
+	Propstats []Propstat `xml:"DAV: propstat"`
+	// TODO: (href*, status)
+	// TODO: error?, responsedescription? , location?
+}
+
+// https://tools.ietf.org/html/rfc4918#section-14.22
+type Propstat struct {
+	XMLName xml.Name    `xml:"DAV: propstat"`
+	Prop    RawXMLValue `xml:"DAV: prop"`
+	Status  string      `xml:"DAV: status"`
+	// TODO: error?, responsedescription?
+}